78 JUNCACEAE. 



A. Leaves neitlier septate nor cquitant. 



1. Leaves not fistulose ; flowers many. 



a. Flowers bracteolafe, inserted singly on the branches of the inflores- 

 cence ; leaves narrowly linear, either flat or subterete and channeled. 



a. Perennials; stem simple (Tenues). 



Seeds long, caudate ; leaves subterete, with a shallow groove above. 



7. /. Vaseyi. 



Seeds not caudate ; leaves flat, but often involute ; lunate in cross- 

 section. 

 Auricles at the summit of the sheaths membranous, whitish ; petals 

 and sepals scarcely spreading. 

 Auricles scarcely produced beyond the insertion, scarcely scarious ; 

 inflorescence open. 

 Perianth 3-4 mm. long, equalling the capsule. 



8. /. interior. 

 Perianth 4.5-5 mm. long, exceeding the capsule. 



9. /. arizonicus. 

 Auricles conspicuously produced beyond the point of insertion ; 



flowers few, congested. 10. /. confusus. 



Auricles cartilaginous, yellowish-brown ; petals and sepals spread- 

 ing. II. J. Dudleyi. 

 §. Annuals; stem branching (Bufonii). 12. /. hufonius. 



b. Flowers not bracteolate, in true heads on the branches of the inflores- 

 cence ; leaves broad and grasslike (Graminifolii). 



13. /. longislylis. 



2. Leaves fistulose (j. c, hollow) ; flowers few, in small heads (Castanei). 

 Stem leafy only at the base, but the uppermost leaf often with a long 



sheath ; petals and sepals about 4 mm. long ; leaves about i mm. in 

 diameter ; lower bract of inflorescence membranous. 



14. /. triglumis. 



Stem more or less leafy ; leaves about 2 mm. in diameter ; perianth 5-6 

 mm. long; lower bracts foliaceous. 15. /. castaneus. 



B. Leaves septate. 



1. Leaves terete, not equitant. 



a. Septa poorly developed; heads 1-3 (see /. triglumis and /. castaneus). 

 h. Septa well developed ; heads usually several (in /. Mertensianus usually 

 only i) (NoDOSi). 

 Inflorescence with short branches ; flowers echinate-spreading or the 

 lowest of the head reflexed ; capsule narrowly lanceolate. 

 Heads 7-8 mm. in diameter; leaf-blades erect; petals usually longer 



than the sepals. 16. /. nodosus. 



Heads over 10 mm. in diameter; leaf-blades usually spreading; sepals 

 longer than the petals. 17. T. Torreyi. 



Inflorescence with elongated branches or in /. Mertensianus with a single 

 head ; flowers erect-ascending ; capsule oblong. 

 Heads several ; leaves terete ; seeds not caudate. 



18. /. truncatus. 

 Heads solitary or rarely 2-2 ; leaves somewhat flattened ; seed usually 

 caudate. 19. /• Mertensianus. 



2. Leaves equitant, laterally flattened, so that one edge is towards the stem 



(Ensifoi.ii). 

 Flower-clusters numerous, small, 5-12-flowered, light-colored. 



20. /. brunncscens. 

 Flower-clusters few, 15-25-flowered. 



Flowers greenish or light-brown ; ligules of the sheath usually without 



auricles. 21. J. parous. 



Flowers fuscous or very dark-brown ; ligules of the sheath produced into 

 small auricles. 22. J. saximontanus. 



I. Juncus filifonnis L. In wet places from Lab. to Alaska, Pa., Utah and 

 Wash.— Reported from Colorado {Coulter), but doubtful. 



